1990 w350 dually 360 gas 727auto, 205tc. Im having an issue where this truck runs perfect cold. When it gets to operating temp. It stumbles, coughs and spits. Ive replaced engine and throttle body temp sensors. My ecm is being remanufactured as I type. 02 sensor? I do believe I have a broken hot wire to ignition switch. Wont start with key have a remote start switch. Thanks for your feedback.

 

Disconnect the O2 sensor, and see if it runs any better.